Sanitary paper products are typically packaged as a roll of paper wound onto a core. In a typical toilet tissue roll, paper is wound on a core having a diameter of 1.6 inches and wound to a diameter of about 4.5 inches and weighs about 0.5 pounds or less. These toilet tissue rolls are generally dispensed from a mandrel by pulling on a loose end of the paper. If the frictional force developed between the mandrel and the inner surface of the core is small, pulling on the loose end of the roll during dispensing can cause the roll to overspin thereby dispensing more paper than is necessary. The prior art approach for solving this problem has been to provide an additional frictional member between the mandrel and the inner surface of the core. In U.S. Pat. No. 2,699,903--Montgomery, an adaptor 1 has resilient fins 2 which frictionally engage the inner surface of core C to prevent overspinning of the roll. Another U.S. Patent, U.S. Pat. No. 4,447,015--Petersen discloses a toilet tissue dispenser in which the mandrel 20 has four ribs 40 which frictionally engage the inner surface of the core to prevent overspinning of the roll. In U.S. Pat. No. 3,770,221--Stern, the embodiment of FIG. 1 discloses a dispenser in which four spring fingers 28 spaced 90.degree. apart are secured to a mandrel and frictionally engage the inner surface of the core. It is believed that all of the above-described prior art dispensers are designed to develop, for a given roll, a constant frictional drag force against the inner surface of the core as the roll is consumed.
In certain applications it may be desirable to use a relatively large diameter roll of paper product. For example, a roll of toilet tissue wound on a core having a diameter of 3 inches and wound to have an overall roll diameter of 14 inches could have an initial weight to about 5 pounds. When such a roll is placed on a mandrel, a relatively large frictional force is developed between the inner surface of the core and the surface of the mandrel. To overcome this frictional force, a relatively large force must be applied to the end of the paper on the roll. If the frictional forces are large enough, the force applied to the end of the paper may cause the sheet to tear before the roll rotates sufficiently to dispense a useful length of the tissue paper. When the roll diameter becomes small because the roll is consumed, the frictional drag on the inner surface of the core is very low and the roll is subject to overspinning as encountered with the prior art small consumer rolls. It can be seen from the above description of the problem that what is desired is to have a relatively low frictional force acting against the inner surface of the core initially and a relatively higher frictional force resisting rotation of the roll as the diameter of the roll is reduced.
It is, therefore, an object of this invention to provide a dispenser for a rolled sanitary paper product in which the frictional force at an inner surface of the core is increased after the roll has been partially consumed.
It is another object of this invention to provide a dispenser for a rolled sanitary paper product in which at some point during the dispensing of the roll, the frictional force developed at an inner surface of the core increases as the weight of the roll decreases.